Color filter array having a green filter layer

ABSTRACT

A color filter array having a green filter layer on a substrate wherein the green filter layer comprises a copper phthalocyanine dye having its absorption maximum at a wavelength of 600 to 700 nm, and a pyridone azo dye having its absorption maximum at a wavelength of 400 to 500 nm; and has a transmittance at a wavelength of 450 nm of 5% or less and that at 535 nm of 62% or more is provided; and the color filter array shows excellent spectroscopic characteristics with respect to green light and has a green filter layer excellent in light fastness.

This application is a Divisional of application Ser. No. 09/893,450,filed on Jun. 29, 2001, now U.S. Pat. No. 6,713,227, the entire contentsof which are hereby incorporated by reference and for which priority isclaimed under 35 U.S.C. § 120; and this application claims priority ofApplication No. 2000-198913 filed in Japan on Jun. 30, 2000 under 35U.S.C. § 119.

BACKGROUND OF THE INVENTION

The present invention relates to color filter arrays for solid-stateimage devices or liquid crystal display devices, and to a method forproducing the same.

As a color filter array formed on a device such as a solid-state imagedevice or a liquid crystal display device, there has been known a colorfilter array (2) constituted of a red filter layer (R), a green filterlayer (G), and a blue filter layer (B) formed so as to be adjoining toeach other in the same plane of a substrate (1) (FIG. 1). In the colorfilter array (2), the filter layers (R), (G), (B) are arranged in astriped pattern (FIG. 2) or a lattice-like pattern (mosaic) (FIG. 3).

A variety of processes for producing such color filter array have beenproposed. Among them, so-called “color resist method” is in widepractical use. In the color resist method, the patterning is effected byexposing a photosensitive resin composition comprising colorants tolight and developing, and the patterning is repeated in sequence in therequired times.

As the photosensitive resin composition which is employed in the colorresist method, those employing pigments as colorants are in wide use.However, such pigments are not suitable for the formation of fine orminute patterns, for they are granular and do not dissolve indevelopers, and developing residue is generated.

As a photosensitive resin composition for obtaining a finely patternedcolor filter array, a photosensitive resin composition employing dyes ascolorants has also been known. For example, Japanese Patent ApplicationLaid-Open No. 6-75375 discloses a negative photosensitive resincomposition comprising dyes, and Japanese Patent Publication No.7-111485 discloses a positive photosensitive resin compositioncomprising 10 to 50%, on a dry weight basis, of a dye soluble in thesolvent used in the positive photosensitive resin composition.(Hereinafter, “JP-A-” is used for indicating Japanese Patent ApplicationLaid-Open, and “JP-B-” is used for indicating Japanese PatentPublication.)

Colorants comprised in photosensitive resin compositions used forproducing color filter arrays, such as those described above, arerequired to have the following two properties.

(1) Good spectroscopic characteristics, that is, showing sufficientabsorption within the predetermined visible ray region and nounnecessary absorption in the other region.

(2) Good light fastness, that is, no burn-in due to the decolorizationof dyes under normal operating conditions

However, none of the dyes employed in conventional photosensitive resincompositions has both of the above-described two properties.

For example, although the green filter layer of a color filter isdesired to have a small transmittance at a wavelength of 450 nm andlarge transmittance at a wavelength of 535 nm, in the conventionalphotosensitive resin compositions, attempts to lower the transmittanceat 450 nm cause a decrease in transmittance at 535 nm, deteriorating thespectroscopic characteristics. The attempts also cause decrease intransmittance at a wavelength of from 350 to 400 nm. As a result, theamount of exposure energy required for the patterning is raised, causinga reduction in the productivity of color filters.

Such problems of conventional photosensitive resin compositions will bementioned below more concretely.

A photosensitive resin composition comprising a copper phthalocyaninedye and a pirazolone azo dye (C.I. Solvent Yellow 88) is described inabove-mentioned JP-B-7-111485. Both dyes are excellent in lightfastness. However, since C.I. Solvent Yellow 88 (pirazolone azo dye) hasrelatively high absorptivity of near-ultraviolet ray employed for theexposure, the amount of the dye in the composition is limited, and thetransmittance of the resulting green filter layer at 450 nm tends tobecome large. In addition, since the dyes do not have sufficient hightransmittance at 535 nm, transmittance with respect to green light ofthe resulting green filter layer tends to decrease. As a result, colorfilters having a green filter layer formed by using such photosensitiveresin composition were not always satisfactory in their performance. Asa matter of fact, according to the gazette, the transmittance of a 2μm-thick green filter layer formed by using such photosensitive resincomposition is 6% at 450 nm, 56% at 535 nm, and 4% at 650 nm.

A colorant having good spectroscopic characteristics is known. However,none of colorants having good spectroscopic characteristics issatisfactory in light fastness. Therefore, it has been difficult tomanufacture a color filter array having a practical green filter layer.

The inventors of the present invention have made intensive and extensivestudies to develop a color filter array having a green filter layerhaving good spectroscopic characteristics as well as good lightfastness. As a result, they have found that the use of at least twotypes of specific dyes realizes the formation of a green filter layersatisfactory both in spectroscopic properties and light fastness. Thepresent invention was accomplished based on this finding.

SUMMARY OF THE INVENTION

The present invention provides a color filter array having a greenfilter layer on a substrate wherein the green filter layer comprises

a copper phthalocyanine dye (hereinafter, referred to as “dye (I)”)having its absorption maximum at a wavelength of 600 to 700 nm, and

a pyridone azo dye (hereinafter, referred to as “dye (II)”) having itsabsorption maximum at a wavelength of 400 to 500 nm; and

has a transmittance at a wavelength of 450 nm of 5% or less and that at535 nm of 62% or more.

The present invention also provides a process for producing the colorfilter array.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1]

FIG. 1 is a schematic view showing a cross-section of a color filterarray in which a green filter layer, a red filter layer, and a bluefilter layer are provided in the same plane of a substrate.

[FIG. 2]

FIG. 2 is a plane schematic view of a color filter array provided with agreen filter layer, a red filter layer, and a blue filter layer arrangedin a striped pattern.

[FIG. 3]

FIG. 3 is a plane schematic view of a color filter array provided with agreen filter layer, a red filter layer, and a blue filter layer arrangedin a mosaic pattern.

[FIG. 4]

FIG. 4 is a plane schematic view of the color filter array obtained inExample 1.

[FIG. 5]

FIG. 5 is a plane schematic view of the color filter array obtained inExample 1.

[FIG. 6]

FIG. 6 is a schematic view illustrating the steps in Example 4.

DESCRIPTION OF REFERENCE NUMERALS

-   1: substrate-   2: color filter array-   3: over coating film-   4: polysilicon electrode-   5: sensor-   6: V resistor-   7: light-shielding film-   8: passivation film-   9: microlens-   R: red filter layer-   G: green filter layer-   B: blue filter layer

EMBODIMENT OF THE INVENTION

As the substrate used in the color filter of the present invention, asilicon wafer and a transparent inorganic glass plate are exemplified.On the silicone wafer, a charge coupled device may be formed.

The color filter array of the present invention has a green filter layeron its substrate.

The green filter layer comprises a dye (I) having its absorption maximumat a wavelength of 600 to 700 nm, and a dye (II) having its absorptionmaximum at a wavelength of 400 to 500 nm. Concrete examples of the dye(I) include compounds represented by the general formula (I):

whereinR¹⁰, R¹¹, R¹², and R¹³ each independently represent a sulfonic acidgroup or its salt group;a sulfonamide group; ora substituted sulfamoyl group represented by the general formula (1):R¹⁴HN—SO₂—  (1)

-   -   Wherein R¹⁴ represents    -   an alkyl group having 2 to 20 carbon atoms, a cyclohexylalkyl        group in which the alkyl chain has 2 to 12 carbon atoms, an        alkylcyclohexyl group in which the alkyl chain has 1 to 4 carbon        atoms, an alkyl group which has 2 to 12 carbon atoms and has        been substituted with an alkoxyl group having 2 to 12 carbon        atoms, an alkylcarboxylalkyl group represented by the general        formula (1-1):        R¹⁵—CO—O—R¹⁶—  (1-1)        -   wherein R¹⁵ represents an alkyl group having 2 to 12 carbon            atoms and R¹⁶ represents an alkylene group having 2 to 12            carbon atoms    -   an alkyloxycarbonylalkyl group represented by the general        formula (1-2):        R¹⁷—O—CO—R¹⁸—  (1-2)        -   wherein R¹⁷ represents an alkyl group having 2 to 12 carbon            atoms and R¹⁸ represents an alkylene group having 2 to 12            carbon atoms    -   a phenyl group substituted with an alkyl group having 1 to 20        carbon atoms, or    -   an alkyl group which has 1 to 20 carbon atoms and has been        substituted with phenyl group;        and each of i, j, k, m independently represent an integer of 0        to 2 with the proviso that i+j+k+m≦4.

Examples of the group represented by R¹⁴ in a compound represented bythe general formula (I) are as follows. Examples of the alkyl grouphaving 2 to 20 carbon atoms include ethyl group, propyl group, n-hexylgroup, n-nonyl group, n-decyl group, n-dodecyl group, 2-ethylhexylgroup, 1,3-dimethylbutyl group, 1-methylbutyl group, 1,5-dimethylhexylgroup, and 1,1,3,3-tetramethylbutyl group. Examples of thecyclohexylalkyl group in which the alkyl chain has 2 to 12 carbon atomsinclude cyclohexylethyl group, 3-cyclohexylpropyl group, and8-cyclohexyloctyl group. Examples of the alkylcyclohexyl group in whichthe alkyl chain has 1 to 4 carbon atoms include 2-ethylcyclohexyl group,2-propylcyclohexyl group, and 2-(n-butyl)cyclohexyl group. Examples ofthe alkyl group which has 2 to 12 carbon atoms and has been substitutedwith an alkoxyl group having 2 to 12 carbon atoms include3-ethoxy-n-propyl group, propoxypropyl group, 4-propoxy-n-butyl group,3-methyl-n-hexyloxyethyl group, and 3-(2-ethylhexyloxy)propyl group.Examples of the phenyl group substituted with an alkyl group having 1 to20 carbon atoms include o-isopropylphenyl group. Examples of the alkylgroup which has 1 to 20 carbon atoms and has been substituted withphenyl group include DL-1-phenylethyl group, benzyl group, and3-phenyl-n-butyl group.

Examples of the alkyl group having 2 to 12 carbon atoms represented byR¹⁵ in the general formula (1-1) or R¹⁷ in the general formula (1-2)include ethyl group, propyl group, n-hexyl group, n-nonyl group, n-decylgroup, n-dodecyl group, 2-ethylhexyl group, 1,3-dimethylbutyl group,1-methylbutyl group, 1,5-dimethylhexyl group, and1,1,3,3-tetramethylbutyl group. Examples of the alkylene grouprepresented by R¹⁶ or R¹⁸ are dimethylene group, trimethylene group,tetramethylene group, pentamethylene group, and hexamethylene group.

Examples of the dye (I) include C.I. Solvent Blue 25, C.I. Solvent Blue55, C.I. Solvent Blue 67, C.I. Acid Blue 249, and C.I. Direct Blue 86.These are used singly or in combination. These dyes (I) have theirabsorption maximum at a wavelength within the range of from 600 to 700nm.

Examples of the dye (II) include compounds represented by the generalformula (II):

wherein R²⁰ represents an alkyl group having 2 to 10 carbon atoms; R²¹,R²², and R²⁴ each independently represents hydrogen atom, methyl group,hydroxyl group, or cyano group: and R²³ represents an alkyl group having1 to 4 carbon atoms.

In a compound represented by the general formula (II), examples of thealkyl group having 2 to 10 carbon atoms and represented by R²⁰ includeethyl group, propyl group, n-hexyl group, n-nonyl group, n-decyl group,n-dodecyl group, 2-ethylhexyl group, 1,3-dimethylbutyl group,1-methylbutyl group, 1,5-dimethylhexyl group, and1,1,3,3-tetramethylbutyl group. Examples of the alkyl group having 1 to4 carbon atoms and represented by R²³ include methyl group, ethyl group,propyl group, and butyl group.

An example of the dyes (II) is C.I. Solvent Yellow 162. Usually, thesedyes (II) are less i-ray absorptive, and have their absorption maximumat a wavelenght of 400 to 500 mm.

The thickness of the green filter layer and the amounts of the dye (I)and the dye (II) comprised therein are controlled so that transmittanceof the filter is 5% or less at a wavelength of 450 nm and 62% or more at535 nm. For example, by making the green filter layer so as to have athickness of about 1.6 to 1.9 μm and a dye (I) content of, per a totalof 100 parts by weight of the dye (I) and the dye (II), 30 to 70 partsby weight, preferably 40 to 50 parts by weight, the transmittance of thegreen filter layer will be 5% or less at 450 nm and 62% or more at 535nm.

For improving light fastness and controlling the color, that is, controlof its spectroscopic characteristics, other dyes may be incorporatedinto the green filter layer. For example, the green filter layer maycomprise a pirazolone azo dye which shows its absorption maximum at awavelength of 400 to 500 nm (hereinafter, referred to as “dye (III)”).Examples of the dye (III) include compounds represented by the generalformula (III):

wherein R³¹ and R³² each represents hydroxyl group or a carboxylic acidgroup; R³⁰ R³³ R³⁴ and R³⁵ each independently represents hydrogen atom,a halogen atom, an alkyl group having 1 to 4 carbon atoms, a sulfonicacid group, an alkyl group having 1 to 4 carbon atoms, or nitro group,andsalts thereof. Incorporation of the dye (III) further improves the lightfastness of the green filter layer.

As the halogen atom represented by R³⁰, R³³, R³⁴, or R³⁵ in a compoundrepresented by the general formula (III), fluorine atom, chlorine atomand bromine atom can be exemplified. Examples of the alkyl group having1 to 4 carbon atoms include methyl group, ethyl group, propyl group, andbutyl group. Examples of the alkoxyl group having 1 to 4 carbon atomsare methoxy group, ethoxy group, propoxy group, and butoxy group.

The dye (III) may be a compound of the general formula (III) or itssalt. As the salt, those with alkaline metals such as sodium andpotassium or with amines such as triethylamine, 2-ethylhexylamine, and1-amino-3-phenylbutane can be exemplified. When at least one of thegroups R³⁰, R³³, R³⁴, and R³⁵ in a compound represented by the generalformula (III) is a sulfonic acid group, usually, its salt is formed atthe position of the sulfonic acid group.

The dye (III) may form a complex through coordination with a chromiumatom. Formation of a complex with a chromium atom further improves thelight fastness.

Examples of the dye (III) are C.I. Acid Yellow 17, C.I. Solvent Orange56, and C.I. Solvent Yellow 82, and these are used singly or incombination. These dyes (III) have their absorption maximum at awavelength of 400 to 500 nm.

When the dye (III) is used, its content is usually 70 parts by weight orless per a total of 100 parts by weight of the dye (I) and the dye (II).If the content of the dye (III) exceeds 70 parts by weight, the degreeof, for example, i-ray absorption rises, which tends to make thepatterning through exposure to light difficult. In addition, the contentof the dye (III) is usually 10 parts by weight or more, for a dye (III)content of less than 10 parts by weight tends to make the improvement ofthe spectroscopic characteristics unsatisfactory.

The green filter layer may comprise a triallylmethane dye (hereinafter,referred to as “dye (IV)”) showing its absorption maximum at awavelength within the range of from 580 to 680 nm. Examples of the dye(IV) include compounds represented by the general formula (IV-1):

wherein R⁴¹, R⁴², R⁴³, and R⁴⁴ each independently represents hydrogenatom, methyl group, or ethyl group; and R⁴⁵ represents a grouprepresented by the general formula (4-1):

wherein R⁴⁶ represents hydrogen atom or amino group;

and R⁴⁷ represents hydrogen atom or hydroxyl group or a grouprepresented by the general formula (4-2):

wherein R⁴⁸ represents hydrogen atom or amino group;

and R⁴⁹ represents hydrogen atom or hydroxyl group; compoundsrepresented by the general formula (IV-2):

wherein R⁴¹⁰ and R⁴¹¹ each independently represents hydrogen atom or analkyl group having 1 to 3 carbon atoms; R⁴¹² represents hydrogen atom ora sulfonic acid group; R⁴¹³ represents hydrogen atom, a sulfonic acidgroup, a carboxylic acid group, an alkyl group having 1 to 3 carbonatoms, an alkoxyl group having 1 to 3 carbon atoms, or a grouprepresented by the general formula (41):—NR⁴¹⁴R⁴¹⁵  (41)

-   -   wherein R⁴¹⁴ and R⁴¹⁵ each independently represents hydrogen        atom, phenyl group, an alkyl group having 1 to 3 carbon atoms or        a phenyl group substituted at the p-position with an alkoxyl        group having 1 to 3 carbon atoms; and        salts thereof.

Incorporation of the dye (IV) can further improve spectroscopiccharacteristics while controlling a transmittance at 650 nm so as to be10% or less with ease.

In a compound of the general formula (IV-2), examples of the alkyl grouphaving 1 to 3 carbon atoms and represented by R⁴¹⁰, R⁴¹¹, R⁴¹³, R⁴¹⁴, orR⁴¹⁵ include methyl group, ethyl group, and propyl group. Examples ofthe alkoxyl group having 1 to 3 carbon atoms and represented by R⁴¹³include methoxy group, ethoxy group, and propoxy group. Examples of thephenyl group substituted at the p-position with an alkoxyl group having1 to 3 carbon atoms and represented by R⁴¹⁴ or R⁴¹⁵ are p-methoxyphenylgroup, p-ethoxyphenyl group, and p-propoxyphenyl group.

The dye (IV) may be a compound represented by the general formula(IV-1), a compound of the general formula (IV-2), or a salt of thecompound of the general formula (IV-1) or (IV-2).

Examples of the salt of a compound of the general formula (IV-2) includethose with alkaline metals such as sodium and potassium or with aminessuch as triethylamine, 2-ethylhexylamine and 1-amino-3-phenylbutane. Thesalt may be formed at the position of —SO₃— residue or at a acid grouprepresented by R⁴¹² or R⁴¹³.

Examples of the compound represented by the general formula (IV-1)include C.I. Acid Green 16, C.I. Acid Blue 108, and C.I. Acid Green 50.Examples of the compound represented by the general formula (IV-2) orits salt include C.I. Acid Blue 7, C.I. Acid Blue 83, C.I. Acid Blue 90,C.I. Solvent Blue 38, C.I. Acid Violet 17, C.I. Acid Violet 49, C.I.Acid Green 3, and C.I. Acid Green 9. These dyes (IV) are used singly orin combination. These dyes (IV) have their absorption maximum at awavelength within the range of from 580 to 680 nm.

In the case where the dye (IV) is used, its content is controlled sothat the transmittance of the green filter layer is 5% or less at 450nm, 62% or more at 535 nm, and 10% or less at 650 nm. Usually, thecontent of the dye (IV) is adjusted so as to be 70 parts by weight orless per a total of 100 parts by weight of the dye (I) and the dye (II).A dye (IV) content exceeding 70 parts by weight tends to result in adecrease in transmittance at 535 nm. Preferably, the content of the dye(IV) is 5 parts by weight or more, for a content of less than 5 parts byweight tends to make adjustment of its transmittance at 650 nm to 10% orless difficult.

The color filter array of the present invention can be produced by anordinary color resist method. For example, it can be produced by aprocess comprising the step of patterning a photosensitive resincomposition comprising colorants. The photosensitive resin compositioncomprises the dye (I) and the dye (II). The amounts of the dye (I) andthe dye (II) comprised in the photosensitive resin composition areindividually the same as those in the desired green filter layer. If thegreen filter layer is desired to comprise other dyes, for example, thedye (III) and the dye (IV), a photosensitive resin compositioncomprising the dye (III) and the dye (IV) is employed. The amounts ofthe dye (III) and the dye (IV) comprised in the photosensitive resincomposition are the same as those in the desired green filter layer. Thetransmittance of the green filter layer after the patterning is 5% orless at 450 nm and 62% or more at 535 nm.

The photosensitive resin composition may be a positive photosensitiveresin composition or a negative photosensitive resin composition.

The positive photosensitive resin composition of the present inventioncomprises, for example, a photoactive compound and an alkali-solubleresin in addition to the above-described dyes.

A photoactive compound used in conventional photosensitive resincompositions can be used in the positive photosensitive resincomposition of the present invention. Examples thereof include esters ofphenolic compounds with o-naphthoquinonediazide sulfonates. Examples ofthe phenolic compounds include compounds represented by the chemicalformula (10).

As the o-naphthoquinonediazide sulfonates,o-naphthoquinonediazide-5-sulfonate ando-naphthoquinonediazide-4-sulfonate can be exemplified.

The term “alkali-soluble resin” refers to resins that dissolve inalkaline developers, and any alkali-soluble resin similar to those usedin conventional photosensitive resin compositions can be employed.Examples of such alkali-soluble resins include novolak resins such asthose of p-cresol novolak resins, novolak resins of p-cresol andm-cresol; novolak resins having the structure represented by the formula(20):

; polyvinylphenol; and copolymers of styrene with vinylphenol.Preferably, a novolak resin is employed as the alkali-soluble resin.

The amounts of the dyes, the photoactive compound, and thealkali-soluble resin comprised in the photosensitive resin compositionare usually 25 to 55 parts by weight, 25 to 55 parts by weight, and 3 to50 parts by weight, per a total of 100 parts by weight of the dyes,photoactive compound, and alkali-soluble resin, respectively.

Into the positive photosensitive resin composition, a curing agent maybe incorporated. Incorporation of the curing agent improves themechanical strength of the pattern formed by using the photosensitiveresin composition.

As the curing agent, usually, a heat curing agent which is cured throughheating is employed. Examples of the heat curing agent include compoundsrepresented by the general formula (30):

wherein Q¹, Q², Q³, and Q⁴ each independently represents hydrogen atom,a hydroxyalkyl group having 1 to 4 carbon atoms, or an alkyl grouphaving 1 to 4 carbon atoms and substituted with an alkoxyl group having1 to 4 carbon atoms; Z represents phenyl group or a group represented bythe general formula (31):Q⁵Q⁶N—  (31)

-   -   wherein Q⁵ and Q⁶ each independently represents hydrogen atom, a        hydroxyalkyl group having 1 to 4 carbon atoms, or an alkyl group        having 1 to 4 carbon atoms and substituted with an alkoxyl group        having 1 to 4 carbon atoms        with the proviso that at least one of Q¹ to Q⁶ is a hydroxyalkyl        group having 1 to 4 carbon atoms or an alkyl group having 1 to 4        carbon atoms and substituted with an alkoxyl group having 1 to 4        carbon atoms.

Examples of the hydroxyalkyl group having 1 to 4 carbon atoms includehydoxymethyl group, hydroxyethyl group, hydroxypropyl group, andhydroxybutyl group. Examples of the alkyl group having 1 to 4 carbonatoms and substituted with an alkoxyl group having 1 to 4 carbon atomsinclude methoxymethyl group, methoxyethyl group, ethoxyethyl group, andpropoxybutyl group.

An example of the compound represented by the general formula (30) ishexamethoxymethylmelamine.

Moreover, compounds of the following chemical formulae (32) to (37) canbe used as the curing agent in the positive photosensitive resincomposition of the present invention, for example.

When the curing agent is used, its content is usually not less than 10parts by weight and not more than 35 parts by weight per a total of 100parts by weight of the dyes, the photoactive compound, and thealkali-soluble resin.

The positive photosensitive resin composition of the present inventionis usually diluted with a solvent.

The solvent is suitably selected according to the solubilities of thedye (I), dye (II), dye (III), dye (IV), photoactive compound,alkali-soluble resin, and curing agent, especially according to thesolubilities of the dye (I), dye (II), dye (III), and dye (IV). Forexample, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate,ethyl cellosolve acetate, diethylene glycol dimethyl ether, ethyleneglycol monoisopropyl ether, propylene glycol monomethyl ether,N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide,N,N′-dimethylformamide, cyclohexane, ethyl acetate, n-butyl acetate,propylene glycolmonoethyl ether acetate, ethyl acetate, ethylpyruvate,ethyl lactate, or the like can be employed. These solvents are usedeither singly or in combination.

The amount of the solvent to be used is usually about 180 to 400 partsby weight per a total of 100 parts by weight of the dyes, photoactivecompound, alkali-soluble resin, and curing agent.

The negative photosensitive resin composition of the present inventioncomprises, for example, a photoreactive acid generator, a curing agent,and an alkali-soluble resin, in addition to the dyes described above.

A photoreactive acid generator use in conventional negativephotoreactive resin compositions can be employed as the photoreactiveacid generator used in the negative photosensitive resin composition ofthe present invention. Examples thereof include compounds represented bythe general formula (40):

wherein Q⁷ represents an alkyl group having 1 to 3 carbon atoms, and Q⁸represents a phenyl group substituted with an alkyl group having 1 to 3carbon atoms or a phenyl group substituted with an alkoxyl group having1 to 3 carbon atoms.

Examples of the alkyl group having 1 to 3 carbon atoms represented by Q⁷include methyl group, ethyl group, and propyl group. An example of thephenyl group substituted with an alkyl group having 1 to 3 carbon atomsand represented by Q⁸ is o-isopropylphenyl group. Examples of the phenylgroup substituted with an alkoxyl group having 1 to 3 carbon atomsinclude p-methoxyphenyl group, p-ethoxylphenyl group, andp-propoxyphenyl group.

Moreover, compounds represented by the chemical formulae (41) to (47):

can also be used as the photo acid generator, for example.

As the curing agent, a heat curing agent which is cured through heatingis usually employed as in the case of conventional negativephotosensitive resin composition. The heat curing agents listed above asexamples for the positive photosensitive resin composition can also beemployed in the negative photosensitive resin composition of the presentinvention.

The alkali-soluble resins listed above as examples for the positivephotosensitive resin composition can also be employed in the negativephotosensitive resin composition of the present invention, as in thecase of conventional negative photosensitive resin composition.

The amounts of the photo acid generator, curing agent, andalkali-soluble resin comprised in the negative photosensitive resincomposition per a total of 100 parts by weight of the dyes,photoreactive acid generator, curing agent, and alkali-soluble resin areas follow. The content of the dyes is usually about 15 to 40 parts byweight, and that of the photo acid generator is usually 0.3 to 5 partsby weight. The amount of the curing agent to be used is usually 10 to 25parts by weight, and the content of the alkali-soluble resin is usually20 to 75 parts by weight.

The negative photosensitive resin composition is usually diluted with asolvent.

The solvent is selected according to the solubilities of the dye (I),dye (II), dye (III), dye (IV), photo acid generator, alkali-solubleresin, and curing agent, especially according to the solubilities of thedye (I), dye (II), dye (III), and dye (IV). The solvent listed above asexamples for the positive photosensitive resin composition can beemployed. The amount of the solvent to be used is usually about 180 to400 parts by weight per a total of 100 parts by weight of the dyes,photo acid generator, curing agent, and alkali-soluble resin.

Since the above-described photosensitive resin composition employs thedye (I) and the dye (II) as its colorants, almost no precipitate isgenerated even if the composition is stored for a long period of time.Consequently, the composition can be applied onto the substratepractically without irregularities. This makes it possible to provide acolor filter array having a green filter layer with a pattern of about0.5 to 2 μm in thickness and about 2 to 20 μm in length of each side.

The patterning is effected, for example, by providing a coat of theabove-described resin composition on a substrate, exposing the coat tolight, and then developing.

The coat is provided on the substrate by applying a dilutedphotosensitive resin composition thereto. The composition is usuallyapplied by spin coating. After the composition has been applied onto thesubstrate, the coat is heated up to, for example, about 80 to 130° C. toevaporate the solvent comprised therein. Thus, a coat of thephotosensitive resin composition is obtained.

Thereafter, the coat is exposed to light. The exposure to light involvesthe use of a mask pattern corresponding to the desired pattern, and iseffected by irradiating the coat with a beam through the mask pattern.As the beam for the exposure of the coat to light, for example, g-ray,i-ray, or the like can be employed. Such an exposure equipment as theg-ray stepper or i-ray stepper may be employed for the exposure. When anegative photosensitive resin composition is used, the coat is heatedafter the exposure to light. When the positive photosensitive resincomposition is used, the coat may be heated after the exposure or maynot be heated. On heating the coat, the heating temperature is, forexample, about 80 to 150° C.

After having been exposed to light, the coat is subjected todevelopment. The development is effected by immersing the substrateprovided with the coat in a developer, as in the case of the use of anordinary photosensitive resin composition. Developer used for patterningconducted by using a conventional photosensitive resin composition canalso be employed in patterning in the present invention. A color filterarray having a green filter layer defined in the desired pattern can beobtained by taking the substrate out of the developer and then washingwith water to remove the developer.

When a positive photosensitive resin composition is used, after havingbeen washed with water, the substrate may be subjected to ultravioletray irradiation. Irradiation of ultraviolet rays can decompose theremaining photoactive compound. Moreover, when the photosensitive resincomposition comprises a heat curing agent, the substrate may be heatedafter having been washed with water. By heating, the mechanical strengthof the formed green filter layer can be improved. The heatingtemperature is usually not lower than 160° C. and not higher than 220°C. Usually, the heating temperature is not higher than the decompositiontemperatures of the dyes.

When a negative photosensitive resin composition is used, the substratemay be heated after having been washed with water. By heating, themechanical strength of the formed green filter layer is improved. Theheating temperature is usually not lower than 160° C. and not higherthan 220° C. Usually, the heating temperature is not higher than thedecomposition temperatures of the dyes.

Thus, a green filter layer in the desired pattern is formed. The otherfilter layers, that is, a red filter layer and a blue filter layer areformed in the same plane of the substrate which has been provided withthe green filter layer, according, for example, to a conventionalmanner. When employing a positive photosensitive resin composition, itis preferred to employ one comprising a curing agent and carry outheating after development, for the strength of the formed green filterlayer is improved. The green filter layer may be formed after the othercolor filter layers have been provided on the substrate.

Thus, a color filter array constituted of the red filter layer, greenfilter layer, and blue filter layer that are formed so as to beadjoining to each other in the same plane of the substrate can beobtained. The color filter array thus obtained is used for a solid-stateimage device, a liquid crystal display device, and the like. Forinstance, in the solid-state image device, if the color filter array isdisposed on the front side of its charge-coupled device, color imagesexcellent in color reproductivity, especially in the reproductivity ofgreen color, can be obtained.

The color filter array of the present invention shows excellentspectroscopic characteristics with respect to green light and has agreen filter layer excellent in light fastness. Moreover, since dyes areemployed as its colorants, the photosensitive resin composition to beemployed for its production generates a less amount of precipitates andis excellent in store stability. As a result, a green filter layer lessin foreign matter content, and uniform in thickness can be produced withease. This color filter array is favorably employed for use in a liquidcrystal display device or a solid-state image device comprising acharge-coupled device.

Hereinafter, the present invention will be described in more detailbased on Examples, but these should by no means be construed as definingthe scope of the present invention.

EXAMPLE 1

After 2.5 parts by weight of C.I. Solvent Blue 67 as the dye (I), 0.3.5parts by weight of C.I. Solvent Yellow 162 as the dye (II), 3.5 parts byweight of C.I. Solvent Yellow 82 as the dye (III), 9 parts by weight ofthe ester of a phenolic compound represented by the chemical formula(10) with o-naphthoquinonediazide-5-sulfonate, as the photoactivecompound, 7.5 parts by weight of a novolak resin of p-cresol as thealkali-soluble resin (weight average molecular weight in terms ofpolystyrene: 6,000), 5 parts by weight of hexamethoxymethylmelamine asthe curing agent, and 70 parts by weight of ethyl lactate as the solventhad been mixed and dissolved, the resulting mixture was filtrated with amembrane filter having a pore size of 0.1 μm to provide a positivephotosensitive resin composition.

A coat was formed by applying the positive photosensitive resincomposition obtained above onto a substrate (silicon wafer) by spincoating and heating at 100° C. for 1 minute to evaporate ethyl lactatetherefrom. The coat had been exposed to light by irradiation of i-raythrough a mask pattern using an exposure equipment (“Nikon NSR i7A”manufactured by Nikon Corp.). Then, the pattern was developed byimmersing the coated substrate in a developer (“SOPD” manufactured bySumitomo Chemical Co., Ltd.) at 23° C. for 1 minute. After thedevelopment, the substrate was washed with water, dried, irradiated withultraviolet rays, and heated to 180° C. for 3 minutes to give a colorfilter array having a green filter layer in a striped-pattern (FIG. 4).The green filter layer has a line width of 1.0 μm and a thickness of 1.8μm.

Thereafter, except using a different mask pattern, the same procedure asabove was repeated to give a color filter array having a green filterlayer formed in a mosaic pattern (FIG. 5). The green filter layer has aline width of 2.0 μm and a thickness of 1.8 μm.

Except that a transparent glass plate was employed as the substrate inplace of a silicon wafer and that the pattern was developed withoutbeing exposed to light, the same procedure as above was repeated to givea green filter layer formed in a thickness of 1.8 μm all over thesubstrate.

EXAMPLE 2

Except for using 0.7 part by weight of C.I. Acid Green 16 as the dye(IV) in addition to C.I. Solvent Blue 67 as the dye (I), C.I. SolventYellow 162 as the dye (II) and C.I. Solvent Yellow 82 as the dye (III),the same procedure as in Example 1 was repeated to give a color filterarray having a striped-pattern green filter layer with a line width of1.0 μm and a thickness of 1.8 μm (FIG. 4), a color filter array having amosaic-pattern green filter layer with a line width of 2.0 μm and athickness of 1.8 μm, and a green filter layer formed in a thickness of1.8 μm all over the substrate.

EXAMPLE 3

After 2.5 parts by weight of C.I. Solvent Blue 67 as the dye (I), 3.5parts by weight of C.I. Solvent Yellow 162 as the dye (II), 3.5 parts byweight of C.I. Solvent Yellow 82 as the dye (III), 0.5 parts by weightof a compound represented by the chemical formula (51):

as the photo acid generator, 7.5 parts by weight of a novolak resin ofp-cresol as the alkali-soluble resin (weight average molecular weight interms of polystyrene: 6,000), 5 parts by weight ofhexamethoxymethylmelamine as the curing agent, and 70 parts by weight ofethyl lactate as the solvent had been mixed and dissolved, the resultingmixture was filtrated with a membrane filter having a pore size of 0.1μm to provide a negative photosensitive resin composition.

A coat was formed by applying the negative photosensitive resincomposition obtained above onto a substrate (silicon wafer) by spincoating and heating at 100° C. for 1 minute to evaporate ethyl lactatetherefrom. The coat had been exposed to light by irradiation of i-raythrough a mask pattern using an exposure equipment (“Nikon NSR i7A”manufactured by Nikon Corp.), followed by heated at 120° C. for 1minute. Then, the pattern was developed by immersing the coatedsubstrate in a developer (“SOPD” manufactured by Sumitomo Chemical Co.,Ltd.) at 23° C. for 1 minute. After the development, the substrate waswashed with water, dried, irradiated with ultraviolet rays, and heatedto 180° C. for 3 minutes to give a color filter array having a greenfilter layer in a striped-pattern. The green filter layer has a linewidth of 1.0 μm and a thickness of 1.8 μm.

Thereafter, except using a different mask pattern, the same procedure asin Example 1 was repeated to give a color filter array having a greenfilter layer formed in a mosaic pattern. The green filter layer has aline width of 2.0 μm and a thickness of 1.8 μm.

Except that a transparent glass plate was employed as the substrate inplace of a silicon wafer and that the exposure to light was conductedwithout using the mask pattern, the same procedure as in Example 1 wasrepeated to give a green filter layer formed in a thickness of 1.8 μmall over the substrate.

EXAMPLE 4

A photosensitive resin composition for forming a green filter layer, aphotosensitive resin composition for forming a red filter layer, and aphotosensitive resin composition for forming a blue filter layer wereprepared according to the respective blending formulations shown below.

(Photosensitive resin composition for forming a red filter layer)Novolak resin 5 parts by weight o-naphthoquinonediazide-4-sulfonate 8parts by weight Hexamethoxymethylmelamine 2 parts by weight Ethyllactate 50 parts by weight N,N′-dimethylformamide 25 parts by weight Acompound represented by the chemical formula (52) 2 parts by weight C.I.Solvent Orange 56 2 parts by weight C.I. Solvent Yellow 82 2 parts byweight C.I. Solvent Yellow 162 2 parts by weight (Photosensitive resincomposition for forming a blue filter layer) Novolak resin 5 parts byweight o-naphthoquinonediazide-4-sulfonate ester 8 parts by weightHexamethoxymethylmelamine 2 parts by weight Ethyl lactate 50 parts byweight N,N′-dimethylformamide 25 parts by weight A compound representedby the chemical formula (52) 3 parts by weight C.I. Solvent Blue 25 3parts by weight C.I. Acid Blue 90 2 parts by weight (Photosensitiveresin composition for forming a green filter layer) Novolak resin 5parts by weight o-naphthoquinonediazide-4-sulfonate ester 8 parts byweight Hexamethoxymethylmelamine 2 parts by weight Ethyl lactate 50parts by weight N,N′-dimethylformamide 25 parts by weight C.I. SolventBlue 25 4 parts by weight C.I. Solvent Yellow 82 2 parts by weight C.I.Solvent Yellow 162 2 parts by weight

The photosensitive resin composition for forming a red filter layerprepared above had been applied onto a silicon wafer provided with acharge-coupled device constituted of a over coating film (3), apolysilicon electrode (4), a sensor (5), a V resistor (6), alight-shielding film (7), and a passivation film (8) by spin coating.Then, its solvent was evaporated off on a baking plate at 100° C.

Thereafter, using an i-ray stepper exposure equipment (“Nikon NSR2205i12D” manufactured by Nikon Corp.), the substrate was irradiated with anultraviolet ray of a wavelength of 365 nm through a reticle (2,000mJ/cm²). Then, the substrate was subjected to development by adeveloping agent (an aqueous solution containing 30 g oftetramethylammonium hydroxide per 1,000 cm³). After the exposed portionhad been removed, the substrate was washed with pure water. Thereafter,using a low-pressure mercury lamp (3,000 mJ/cm²), ultraviolet rays wereirradiated all over the substrate, and the substrate was then heated ona baking plate at 180° C. for 10 minutes to form a red filter layer(FIG.6 (a)).

Except for using the photosensitive resin composition for forming a bluefilter layer prepared above instead of the photosensitive resincomposition for forming a red filter layer, the same procedure as abovewas repeated to form a blue filter layer (FIG. 6 (b)).

Except for using the photosensitive resin composition for forming agreen filter layer prepared above, the same procedure as above wasrepeated to form a green filter layer and consequently a color filterarray(FIG. 6 (c), (d)).

A microlens was formed on the color filter array in a conventionalmanner to give a solid-state image device. The thickness of the greenfilter layer of the color filter array at the solid-state image devicewas 1.7 μm. The color filter array at this solid-state image deviceshowed good spectroscopic characteristics (FIG. 6 (e)).

In the same manner as that described above, a green filter layer(thickness: 1.7 μm) was formed all over a quartz wafer.

EXAMPLE 5

Except that the following photosensitive resin composition was employedas the photosensitive resin composition for forming a green filterlayer, the same procedure as that in Example 4 was repeated to give asolid-state image device, and a green filter layer (thickness: 1.7 μm)was formed.

(Photosensitive resin composition for forming a green filter layer)Novolak resin 5 parts by weight o-naphthoquinonediazide-4-sulfonateester 8 parts by weight Hexamethoxymethylmelamine 2 parts by weightEthyl lactate 50 parts by weight N,N′-dimethylformamide 25 parts byweight C.I. Solvent Blue 25 (dye (I)) 3 parts by weight C.I. SolventYellow 82 (dye (III)) 2 parts by weight C.I. Solvent Yellow 162 (dye(II)) 2 parts by weight C.I. Acid Green 16 (dye (IV) 1 part by weight

The color filter array at the solid-state image device obtained aboveshowed improved spectroscopic characteristics.

Measurements made on the green filter layer (thickness: 1.7 μm) formedon the quartz wafer revealed its transmittance as to be 1% at awavelength of 450 nm, 67% at a wavelength of 535 nm, and 4% at awavelength of 650 nm.

COMPARATIVE EXAMPLE 1

After 2.5 parts by weight of C.I. Solvent Blue 67 as the dye (I), 7parts by weight of C.I. Acid Yellow 40 as a dye, 9 parts by weight ofthe ester of a phenolic compound represented by the chemical formula(30) with o-naphthoquinonediazide-5-sulfonate, as the photoactivecompound, 7.5 parts by weight of the novolak resin of p-cresol (weightaverage molecular weight: 6,000 on polystyrene basis), as thealkali-soluble resin, 5 parts by weight of hexamethoxymethylmelamine asthe curing agent, and 70 parts by weight of ethyl lactate as the solventhad been mixed and dissolved, the resulting mixture was filtrated with amembrane filter having a pore size of 0.1 μm to give a positivephotosensitive resin composition.

Thereafter, except for using the positive photosensitive resincomposition obtained above, the same procedure as in Example 1 wasrepeated to give a color filter array having a striped pattern greenfilter layer having a line width of 1.0 μm and a thickness of 1.8 μm; acolor filter array having a mosaic pattern green filter layer having aline width of 2.0 μm and a thickness of 1.8 μm; and a color filter arrayall over of which is provided with a 1.8 μm-thick green filter layer.

Evaluation

(1) Spectroscopic Characteristics

The color filter arrays each provided with a green filter layer all overits substrate and obtained in Examples and Comparative Example weresubjected to measurement of light transmittance at 450 nm, 535 nm, and650 nm. The results are shown in Table 1.

TABLE 2 Light transmittance (%) Wavelength (nm) 450 535 650 Example 11.5 74 15 Example 2 0.4 67 16 Example 3 1.5 75 15 Example 4 2.0 68 13Example 5 2.0 64 8 Comparative 17 74 15 example 1(2) Light Fastness

An ultraviolet ray-blocking filter (“colored optical glass L38”manufactured by Hoya Corp. Capable of blocking light of a wavelength of380 nm or shorter) was disposed in front of each of the color filterarrays obtained in Examples and Comparative Example and provided with agreen filter layer all over its substrate, followed by irradiating lightat 1,000,000 lx·hour. “Sun tester XF 180 CPS” manufactured by ShimadzuCorp. was employed as the light source. The light transmittance of eachcolor filter array after the irradiation was measured at a wavelength of450 nm, 535 nm, and 650 nm. The results are shown in Table 2.

TABLE 1 Light transmittance (%) Wavelength (nm) 450 535 650 Example 10.4 68 13 Example 2 0.4 67 5 Example 3 0.4 69 13 Example 4 1.0 70 13Example 5 1.0 67 4 Comparative 0.4 68 13 example 1

1. A color filter array having a green filter layer on a substratewherein the green filter layer comprises a copper phthalocyanine dyehaving its absorption maximum at a wavelength of 600 to 700 nm, and apyridone azo dye having its absorption maximum at a wavelength of 400 to500 nm; and has a transmittance at a wavelength of 450 nm of 5% or lessand that at 535 nm of 62% or more.
 2. The color filter array having agreen filter layer on a substrate according to claim 1, wherein thegreen filter layer further comprises a pirazolone azo dye showing itsabsorption maximum at a wavelength of 400 to 500 nm.
 3. The color filterarray having a green filter layer on a substrate according to claim 2,wherein the green filter layer further comprises a triallylmethane dyeshowing its absorption maximum at a wavelength within the range of from580 to 680 nm, and has a transmittance of 5% or less at 450 nm, that of62% or more at 535 nm and that of 10% or less at 650 nm.
 4. The colorfilter array having a green filter layer on a substrate according toclaim 1, wherein the green filter layer further comprises atriallylmethane dye showing its absorption maximum at a wavelengthwithin the range of from 580 to 680 nm, and has a transmittance of 5% orless at 450 nm, that of 62% or more at 535 nm and that of 10% or less at650 nm.
 5. A process for producing a color filter array having a greenfilter layer on a substrate which comprises the step of patterning aphotosensitive resin composition comprising a copper phthalocyanine dyehaving its absorption maximum at a wavelength of 600 to 700 nm, and apyridone azo dye having its absorption maximum at a wavelength of 400 to500 nm to form the green filter layer having a transmittance at awavelength of 450 nm of 5% or less and that at 535 nm of 62% or more. 6.The process according to claim 5, wherein the photosensitive resincomposition further comprises a pirazolone azo dye showing itsabsorption maximum at a wavelength of 400 to 500 nm.
 7. The processaccording to claim 6, wherein the photosensitive resin compositionfurther comprises triallylmethane dye showing its absorption maximum ata wavelength within the range of from 580 to 680 nm, and the greenfilter layer has a transmittance of 5% or less at 450 nm, that of 62% ormore at 535 nm and that of 10% or less at 650 nm.
 8. The processaccording to claim 5, wherein the photosensitive resin compositionfurther comprises triallylmethane dye showing its absorption maximum ata wavelength within the range of from 580 to 680 nm, and the greenfilter layer has a transmittance of 5% or less at 450 nm, that of 62% ormore at 535 nm and that of 10% or less at 650 nm.